/*
 * Copyright (c) Contributors, http://opensimulator.org/
 * See CONTRIBUTORS.TXT for a full list of copyright holders.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the OpenSim Project nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

using System;
using System.Collections.Generic;
using System.IO;
using System.Reflection;
using System.Text.RegularExpressions;
using libsecondlife;
using log4net;
using NHibernate;
using NHibernate.Cfg;
using NHibernate.Expression;
using NHibernate.Mapping.Attributes;
using NHibernate.Tool.hbm2ddl;
using OpenSim.Framework;
using Environment=NHibernate.Cfg.Environment;

namespace OpenSim.Data.NHibernate
{
    public class NHibernateInventoryData: IInventoryData
    {
        private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);

        private Configuration cfg;
        private ISessionFactory factory;

        /// <summary>
        /// Initialises the interface
        /// </summary>
        public void Initialise(string connect)
        {
            // Split out the dialect, driver, and connect string
            char[] split = {';'};
            string[] parts = connect.Split(split);
            if (parts.Length != 3) {
                // TODO: make this a real exception type
                throw new Exception("Malformed Inventory connection string '" + connect + "'");
            }
            
            // Establish NHibernate Connection
            cfg = new Configuration();
            cfg.SetProperty(Environment.ConnectionProvider, 
                            "NHibernate.Connection.DriverConnectionProvider");
            cfg.SetProperty(Environment.Dialect, 
                            "NHibernate.Dialect." + parts[0]);
            cfg.SetProperty(Environment.ConnectionDriver, 
                            "NHibernate.Driver." + parts[1]);
            cfg.SetProperty(Environment.ConnectionString, parts[2]);
            cfg.AddAssembly("OpenSim.Data.NHibernate");

            HbmSerializer.Default.Validate = true;
            using ( MemoryStream stream = 
                    HbmSerializer.Default.Serialize(Assembly.GetExecutingAssembly()))
                cfg.AddInputStream(stream);
            
            // If uncommented this will auto create tables, but it
            // does drops of the old tables, so we need a smarter way
            // to acturally manage this.

            // new SchemaExport(cfg).Create(true, true);

            factory  = cfg.BuildSessionFactory();

            InitDB();
        }


        private void InitDB()
        {
            string regex = @"no such table: Inventory";
            Regex RE = new Regex(regex, RegexOptions.Multiline);
            try {
                using(ISession session = factory.OpenSession()) {
                    session.Load(typeof(InventoryItemBase), LLUUID.Zero);
                }
            } catch (ObjectNotFoundException e) {
                // yes, we know it's not there, but that's ok
            } catch (ADOException e) {
                Match m = RE.Match(e.ToString());
                if(m.Success) {
                    // We don't have this table, so create it.
                    new SchemaExport(cfg).Create(true, true);
                }
            }
        }


        /*****************************************************************
         *
         *   Basic CRUD operations on Data 
         * 
         ****************************************************************/

        // READ

        /// <summary>
        /// Returns an inventory item by its UUID
        /// </summary>
        /// <param name="item">The UUID of the item to be returned</param>
        /// <returns>A class containing item information</returns>
        public InventoryItemBase getInventoryItem(LLUUID item)
        {
            using(ISession session = factory.OpenSession()) {
                try {
                    return session.Load(typeof(InventoryItemBase), item) as InventoryItemBase;
                } catch {
                    m_log.ErrorFormat("Couldn't find inventory item: {0}", item);
                    return null;
                }
            }
        }

        /// <summary>
        /// Creates a new inventory item based on item
        /// </summary>
        /// <param name="item">The item to be created</param>
        public void addInventoryItem(InventoryItemBase item)
        {
            if (!ExistsItem(item.ID)) {
                using(ISession session = factory.OpenSession()) {
                    using(ITransaction transaction = session.BeginTransaction()) {
                        session.Save(item);
                        transaction.Commit();
                    }
                }
            } else {
                m_log.ErrorFormat("Attempted to add Inventory Item {0} that already exists, updating instead", item.ID);
                updateInventoryItem(item);
            }
        }

        /// <summary>
        /// Updates an inventory item with item (updates based on ID)
        /// </summary>
        /// <param name="item">The updated item</param>
        public void updateInventoryItem(InventoryItemBase item)
        {
            if (ExistsItem(item.ID)) {
                using(ISession session = factory.OpenSession()) {
                    using(ITransaction transaction = session.BeginTransaction()) {
                        session.Update(item);
                        transaction.Commit();
                    }
                }
            } else {
                m_log.ErrorFormat("Attempted to add Inventory Item {0} that already exists", item.ID);
            }
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="item"></param>
        public void deleteInventoryItem(LLUUID itemID)
        {
            using(ISession session = factory.OpenSession()) {
                using(ITransaction transaction = session.BeginTransaction()) {
                    session.Delete(itemID);
                    transaction.Commit();
                }
            }
        }


        /// <summary>
        /// Returns an inventory folder by its UUID
        /// </summary>
        /// <param name="folder">The UUID of the folder to be returned</param>
        /// <returns>A class containing folder information</returns>
        public InventoryFolderBase getInventoryFolder(LLUUID folder)
        {
            using(ISession session = factory.OpenSession()) {
                try {
                    return session.Load(typeof(InventoryFolderBase), folder) as InventoryFolderBase;
                } catch {
                    m_log.ErrorFormat("Couldn't find inventory item: {0}", folder);
                    return null;
                }
            }
        }

        /// <summary>
        /// Creates a new inventory folder based on folder
        /// </summary>
        /// <param name="folder">The folder to be created</param>
        public void addInventoryFolder(InventoryFolderBase folder)
        {
            if (!ExistsFolder(folder.ID)) {
                using(ISession session = factory.OpenSession()) {
                    using(ITransaction transaction = session.BeginTransaction()) {
                        session.Save(folder);
                        transaction.Commit();
                    }
                }
            } else {
                m_log.ErrorFormat("Attempted to add Inventory Folder {0} that already exists, updating instead", folder.ID);
                updateInventoryFolder(folder);
            }
        }

        /// <summary>
        /// Updates an inventory folder with folder (updates based on ID)
        /// </summary>
        /// <param name="folder">The updated folder</param>
        public void updateInventoryFolder(InventoryFolderBase folder)
        {
            if (ExistsFolder(folder.ID)) {
                using(ISession session = factory.OpenSession()) {
                    using(ITransaction transaction = session.BeginTransaction()) {
                        session.Update(folder);
                        transaction.Commit();
                    }
                }
            } else {
                m_log.ErrorFormat("Attempted to add Inventory Folder {0} that already exists", folder.ID);
            }
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="folder"></param>
        public void deleteInventoryFolder(LLUUID folderID)
        {
            using(ISession session = factory.OpenSession()) {
                using(ITransaction transaction = session.BeginTransaction()) {
                    session.Delete(folderID.ToString());
                    transaction.Commit();
                }
            }
        }

        // useful private methods
        private bool ExistsItem(LLUUID uuid)
        {
            return (getInventoryItem(uuid) != null) ? true : false;
        }

        private bool ExistsFolder(LLUUID uuid)
        {
            return (getInventoryFolder(uuid) != null) ? true : false;
        }

        public void Shutdown()
        {
            // TODO: DataSet commit
        }

        /// <summary>
        /// Closes the interface
        /// </summary>
        public void Close()
        {
        }

        /// <summary>
        /// The plugin being loaded
        /// </summary>
        /// <returns>A string containing the plugin name</returns>
        public string getName()
        {
            return "NHibernate Inventory Data Interface";
        }

        /// <summary>
        /// The plugins version
        /// </summary>
        /// <returns>A string containing the plugin version</returns>
        public string getVersion()
        {
            Module module = GetType().Module;
            string dllName = module.Assembly.ManifestModule.Name;
            Version dllVersion = module.Assembly.GetName().Version;


            return
                string.Format("{0}.{1}.{2}.{3}", dllVersion.Major, dllVersion.Minor, dllVersion.Build,
                              dllVersion.Revision);
        }

        // Move seems to be just update

        public void moveInventoryFolder(InventoryFolderBase folder)
        {
            updateInventoryFolder(folder);
        }

        public void moveInventoryItem(InventoryItemBase item)
        {
            updateInventoryItem(item);
        }
        


        /// <summary>
        /// Returns a list of inventory items contained within the specified folder
        /// </summary>
        /// <param name="folderID">The UUID of the target folder</param>
        /// <returns>A List of InventoryItemBase items</returns>
        public List<InventoryItemBase> getInventoryInFolder(LLUUID folderID)
        {
            using(ISession session = factory.OpenSession()) {
                // try {
                    ICriteria criteria = session.CreateCriteria(typeof(InventoryItemBase));
                    criteria.Add(Expression.Eq("Folder", folderID) );
                    List<InventoryItemBase> list = new List<InventoryItemBase>();
                    foreach (InventoryItemBase item in criteria.List())
                    {
                        list.Add(item);
                    }
                    return list;
//                 } catch {
//                     return new List<InventoryItemBase>();
//                 }
            }
        }

        public List<InventoryFolderBase> getUserRootFolders(LLUUID user)
        {
            return new List<InventoryFolderBase>();
        }

        // see InventoryItemBase.getUserRootFolder
        public InventoryFolderBase getUserRootFolder(LLUUID user)
        {
            using(ISession session = factory.OpenSession()) {
                //                try {
                    ICriteria criteria = session.CreateCriteria(typeof(InventoryFolderBase));
                    criteria.Add(Expression.Eq("ParentID", LLUUID.Zero) );
                    criteria.Add(Expression.Eq("Owner", user) );
                    foreach (InventoryFolderBase folder in criteria.List())
                    {
                        return folder;
                    }
                    m_log.ErrorFormat("No Inventory Root Folder Found for: {0}", user);
                    return new InventoryFolderBase();
//                 } catch {
//                     return new InventoryFolderBase();
//                 }
            }
        }
        
        /// <summary>
        /// Append a list of all the child folders of a parent folder 
        /// </summary>
        /// <param name="folders">list where folders will be appended</param>
        /// <param name="parentID">ID of parent</param>
        private void getInventoryFolders(ref List<InventoryFolderBase> folders, LLUUID parentID)
        {
            using(ISession session = factory.OpenSession()) {
                // try {
                    ICriteria criteria = session.CreateCriteria(typeof(InventoryFolderBase));
                    criteria.Add(Expression.Eq("ParentID", parentID) );
                    foreach (InventoryFolderBase item in criteria.List())
                    {
                        folders.Add(item);
                    }
                    //                } catch {
                    // m_log.ErrorFormat("Can't run getInventoryFolders for Folder ID: {0}", parentID);
                    //  }
            }
        }

        /// <summary>
        /// Returns a list of inventory folders contained in the folder 'parentID'
        /// </summary>
        /// <param name="parentID">The folder to get subfolders for</param>
        /// <returns>A list of inventory folders</returns>
        public List<InventoryFolderBase> getInventoryFolders(LLUUID parentID)
        {
            List<InventoryFolderBase> folders = new List<InventoryFolderBase>();
            getInventoryFolders(ref folders, parentID);
            return folders;
        }

        // See IInventoryData
        public List<InventoryFolderBase> getFolderHierarchy(LLUUID parentID)
        {
            List<InventoryFolderBase> folders = new List<InventoryFolderBase>();
            getInventoryFolders(ref folders, parentID);

            for (int i = 0; i < folders.Count; i++)
                getInventoryFolders(ref folders, folders[i].ID);
            
            return folders;
        }
    }
}